Section 10. Electrical
Eclipse 5OO Systems Manual
Copyright
© — Eclipse Aviation Corporation
224
Version 2.0 April 2007
ECB STATES
Table 30. Electronic Circuit Breaker States
STATE
CONDITION
INDICATION
AUTO/ON
Normal state
White outline/green interior
AUTO/OFF
ECB turned off by the ACS
White outline/gray interior
TRIPPED
ECB off due to circuit fault
Amber
PULLED
ECB opened by the pilot
Gray
COLLARED
ECB locked out by a maintenance technician White outline/cyan interior
10.5 SYSTEM DESCRIPTION
10.5.1 Starter/Generator Units
A starter/generator is mechanically driven by each engine through the accessory
gearbox. Power from the starter/generators is fed to the left and right Generator
Control Units (GCUs).
The starter/generators serve as electric starter motors for the engines. During engine
start, the left or right GCU use Direct Current (DC) power from the start battery to
drive the starter/generator as a motor. The resulting mechanical torque is applied
through the engine’s accessory gearbox to start the engine.
Either starter/generator can supply power for the entire airplane, with the exception of
the air conditioning system. (The air conditioning compressor is load shed during
single generator operation)
10.5.2 Generator Control Units (GCUs)
The left and right Generator Control Units are located in the aft compartment outside
the pressure vessel and control the starter/generators during engine start. The
GCUs automatically switch from the start mode to generator mode at a specific
engine cut-off speed and regulate starter/generator power from 30 volts to 28.5 volts
DC depending on engine speed and electrical load.
The GCUs also provide detection and protection for the following electrical faults:
Ground fault
Over- and under-voltage from the S/Gs
Reverse Current
Overspeed
Open ground
10.5.3 Batteries
Two identical 24 volt DC, 22 amp sealed, maintenance-free lead acid batteries are
located in the nose compartment outside the pressure vessel. Both batteries are
charged when the generators are operating. When external power is connected,
battery charging requires both BATT switches to be ON.
In the event of a loss of both starter/generators and/or GCUs, the two batteries
provide a minimum of 30 minutes power to essential systems.
During normal operation the batteries “float” on the buses to minimize voltage
transients that may be caused by electrical loads being switched on or off.